﻿112 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  The 
  bedding 
  and 
  upper 
  contact 
  lines 
  are 
  irregular. 
  Thick- 
  

   ness 
  14-15 
  feet. 
  

  

  5 
  Compact, 
  finely 
  crystalline 
  and 
  homogeneous 
  dolomitic 
  rock, 
  

   showing 
  traces 
  of 
  fossils 
  and 
  slickensides. 
  Beds 
  showing 
  S 
  t 
  r 
  o 
  - 
  

   matopora 
  common. 
  In 
  places 
  the 
  rock 
  has 
  a 
  porous 
  appear- 
  

   ance 
  and 
  is 
  rich 
  in 
  geoditic 
  cavities, 
  which 
  are 
  fined 
  with 
  dolomite 
  

   and 
  calcite 
  crystals. 
  Thickness 
  19 
  feet. 
  

  

  This 
  stratum 
  forms 
  the 
  lower 
  portion 
  of 
  the 
  cliff 
  at 
  the 
  first 
  cut 
  

   on 
  the 
  gorge 
  road, 
  and 
  the 
  basal 
  part 
  of 
  the 
  mass 
  left 
  standing 
  on 
  

   the 
  river 
  side. 
  Heads 
  of 
  Stromatopora 
  may 
  be 
  seen 
  in 
  this 
  

   rock, 
  some 
  of 
  the 
  geoditic 
  cavities 
  having 
  replaced 
  this 
  fossil. 
  This 
  

   is 
  about 
  the 
  summit 
  of 
  the 
  beds 
  exposed 
  in 
  the 
  quarry 
  at 
  the 
  end 
  oi: 
  

   the 
  railroad 
  section. 
  

  

  6 
  Earthy, 
  compact 
  dolomite 
  in 
  thin 
  layers, 
  which 
  give 
  the 
  clifif 
  

   the 
  appearance 
  of 
  a 
  stone 
  wall. 
  Toward 
  the 
  top 
  the 
  rock 
  becomes 
  

   more 
  compact 
  and 
  heavy 
  bedded, 
  this 
  giving 
  the 
  appearance 
  of 
  an 
  

   overlying 
  stratum. 
  This 
  rock 
  is 
  full 
  of 
  geodes 
  lined 
  with 
  pearl 
  spar 
  

   or 
  dolomite, 
  the 
  cavities 
  ranging 
  in 
  size 
  up 
  to 
  that 
  of 
  a 
  fist 
  or 
  larger. 
  

   The 
  beds 
  are 
  generally 
  less 
  than 
  a 
  foot 
  in 
  thickness, 
  the 
  average 
  

   being 
  from 
  3 
  to 
  6 
  inches. 
  Toward 
  the 
  top 
  of 
  the 
  cut, 
  the 
  rock 
  

   becomes 
  more 
  compact 
  and 
  finely 
  crystalline, 
  but 
  otherwise 
  remains 
  

   similar. 
  Pearl 
  spar 
  geodes 
  remain 
  common 
  to 
  the 
  top. 
  The 
  thick- 
  

   ness 
  of 
  this 
  mass, 
  at 
  the 
  beginning 
  of 
  the 
  gorge 
  road, 
  is 
  about 
  45 
  

   feet. 
  

  

  The 
  total 
  thickness 
  of 
  the 
  limestone 
  exposed 
  on 
  the 
  gorge 
  road 
  is 
  

   in 
  the 
  neighborhood 
  of 
  no 
  feet. 
  This 
  is 
  double 
  the 
  thickness 
  found 
  

   at 
  the 
  quarry, 
  the 
  distance 
  between 
  the 
  two 
  points 
  in 
  a 
  straight 
  line 
  

   being 
  about 
  three 
  miles 
  or 
  nearly 
  four 
  following 
  the 
  curvature 
  of 
  the 
  

   river. 
  The 
  rate 
  of 
  increase 
  in 
  thickness, 
  or 
  the 
  amount 
  of 
  dip 
  of 
  the 
  

   strata 
  is 
  therefore 
  about 
  20 
  feet 
  to 
  the 
  mile. 
  

  

  Almost 
  the 
  only 
  recognizable 
  fossils 
  found 
  in 
  these 
  limestones,, 
  

   excepting 
  the 
  crinoid 
  fragments, 
  are 
  the 
  hydro-coralline 
  St 
  r 
  o 
  m 
  a 
  - 
  

   topora 
  (concentrica 
  Hall) 
  and 
  the 
  coral 
  Favosites. 
  

   Both 
  occur 
  in 
  the 
  middle 
  and 
  upper 
  portions 
  of 
  the 
  exposed 
  mass, 
  

   and 
  may 
  generally 
  be 
  seen 
  in 
  the 
  weathered 
  upper 
  surfaces 
  of 
  the 
  

   limestone 
  beds. 
  Thus 
  wherever 
  these 
  beds 
  are 
  exposed 
  on 
  the 
  sur- 
  

  

  